[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2002-213545
In a quest to improve fuel efficiency of a vehicle on which an automatic transmission apparatus is installed, to improve power transmission performance of this automatic transmission apparatus, to obtain smooth transmission, or to improve the comfort of driving the vehicle, for example, it is desired to increase the number of speeds (transmission gear ratios), and evenly distribute the transmission gear ratios over the entire range of the output rotational speed.
In an automatic transmission apparatus of a first aspect according to Patent Document 1, a multiple planetary reduction gear device, in which a sun gear connected to an input shaft is intermeshed with a small diameter pinion, the small diameter pinion is intermeshed with a first ring gear, and a large diameter pinion coaxial and integral with the small diameter pinion intermeshes with a second ring gear, is connected with a Simpson-type multiple planetary transmission gear device having: one single pinion planetary gear device having a ring gear connected to a carrier supporting the above-mentioned pinion; and the other single pinion planetary gear device having a sun gear connected to a sun gear of said one single pinion planetary gear device.